Thin Centipede Lawn

Another culprit is Nematodes. Take the samples from where the grass is still green not the dried out areas. This problem can be treated for. I would like to see the Centipede mildly dethatched(blades set far apart, not very low into the grass, and one direction only). Fertilized with a fertilizer containing Ammonium nitrogen, Potassium not as Potassium Chloride, Iron, Manganese, and mowing with a very sharp rotary blade at 2" or else a reel mower set to 3/4". If the Centipede is still declining and looking poor in spite of this gentle treatment, then I look at the possibility of pests such as Nematodes. Is your soil very dry and sandy? Another pest is known as Ground Pearls. These are Scale insects that attach to the root system and drain the Centipede grass of its nutrition. That can also be treated for, but I have a hard time blaming decline on pests of any kind unless the grass is grown under optimal conditions.

3/4 is good. You can use the GM 1600 for that. Have you been using it for the 1" height? My understanding is that a GM will go up to an inch or more.

That might help with the thatch. I have gone into previously rotary mowed Centipede with the GM and worked the HOC down from 2-3" to 3/4". First mowing at 1" looked scary for a week or two. Then I got the fairway look once I got it down to 3/4" at the next mowing.

and the way a rotary mower works. I dislike what rotary mowers do to warm season turf. They work well for Tall Fescue because that grass is normally healthiest at 4". On Centipede, some of your "scalping" is from the rotary blades catching the stolons and yanking them. Especially if you are trying to mow at 2".